A repetition is often shortened in speech to Rep. As in how many times you repeat a movement.
A set is how many repetitions you maintain in that set before taking rest.
Rest is the time between exercise where you are allowing your muscles to recover from the activity and contractions you just put it through.
People often do exercises in sets of three. You can do four, eight, sixteen if you like. How long do you want to be at the gym? What kind of lifter are you?
Weightlifters are the general population that lifts weight to burn fat, build lean muscle mass, and gain a sizable about of strength for everyday tasks. This includes all sorts of training and is the most popular kind of movements taught in group fitness classes and executed by people in gym settings.
Weightlifters rep range can be 5 or 20 reps. They can use really light weights and do high reps to challenge muscle endurance. Or they can have a moderate amount of weight and stay somewhere in the 8-10 rep range for sustained strength and muscle development, and still there are many who continue to add weight and intensity going heavy for lighter reps.
There is no one way to train, and even when you find something that works, be ready when you’ll need to change it. Never get stuck in a rep scheme.
Body-builders want to build muscle. It’s in their name. They will typically lift 8 – 12 reps for as many sets as their body will allow. Sometimes they train to failure.
Training to Failure – Training beyond the point that their muscles can create a contraction and complete the exercise. So if you were doing something as simple as jump squats in sets of ten. You would do as many sets until you could not complete the given reps. There is a lot of thought that this is the key to muscle growth and the best way to recruit muscle fibers that wouldn’t otherwise get involved/recruited.
Power Lifters lift as much as they can. We’re not talking the extra five pounds you add on the cable column. This is serious lifting, but they only lift for a short period of time and take a lot of rest. It is not uncommon that they may do 1 Rep of their maximal effort. THAT IS AS MUCH WEIGHT AS THEY CAN MOVE. It is not advisable to power lift solo and proper form is imperative to avoid injury. They are not lifting for aesthetics. They are lifting so that, if they needed to move a car, they would be able to…maybe.. 😉